The Formosa Air Battle, 12–16 October 1944, was a series of large-scale aerial engagements between carrier air groups of the United States Navy Fast Carrier Task Force and Japanese land-based air forces of the Imperial Japanese Navy (IJN) and Imperial Japanese Army (IJA). The battle consisted of American air raids against Japanese military installations on Formosa (Taiwan) during the day and Japanese air attacks at night against American ships. Japanese losses exceeded 300 planes destroyed in the air, while American losses amounted to fewer than 100 aircraft destroyed and two cruisers damaged. This outcome effectively deprived the Japanese Navy's Combined Fleet of air cover for future operations, which proved decisive during the Battle of Leyte Gulf later in October.

Taiwan, officially the Republic of China (ROC), is a country in East Asia. It is located at the junction of the East and South China Seas in the northwestern Pacific Ocean, with the People's Republic of China (PRC) to the northwest, Japan to the northeast, and the Philippines to the south. The territories controlled by the ROC consist of 168 islands with a combined area of 36,193 square kilometres. The main island of Taiwan, also known as Formosa, has an area of 35,808 square kilometres, with mountain ranges dominating the eastern two-thirds and plains in the western third, where its highly urbanized population is concentrated. The capital, Taipei, forms along with New Taipei City and Keelung the largest metropolitan area. With around 23.9 million inhabitants, Taiwan is among the most densely populated countries.